Slavery was on is way out by the time it was reintroduced with a racist twist by the various West India co.
Looking carefully at history, we see no necessary or linear sequence of economic systems. We do see the birth, evolution and death of all systems, but in their deaths, each system can give way to any or all of the other systems (and possibly new ones). Slavery, feudalism, capitalism etc have arisen and passed away giving rise to one another (and still other systems). Capitalism may endure a while longer (even as it is failing growing numbers who turn against it) or it may dissolve into slavery and/or other systems or shore itself up a while longer by partnering with such systems. No fatalistic inherent dynamic dictates any order; it depends on how human beings experience, think through and act upon the systems in which they find themselves.